1. Field of the Invention
The present invention relates to bulk material transport bags. More particularly, the present invention relates to an improved bulk material transport bag when filled, due to a unique closure feature, enables the bag to remain closed as a flat top fully packed bag with enhanced stackability.
2. General Background
In the present state of the art of bulk bags, most of the bulk bags constructed incorporate a design which makes the bag practically impossible to totally fill. In bags which are being filled with bulk material, through an upper inlet spout, such bags would normally have a loose, non- pre-formed liner inserted into the bag, for receiving bulk material in order to avoid contamination. In order to fill, the bottom discharge would be tied off, and the liner would lay substantially loose in the bottom of the bag. Once the bag inlet spout has been positioned for receiving the material, the liner would normally be extending out of the top of the spout, so that the material can be poured into the bag with the liner conforming to the shape of fabric bag. In liners which are simply placed into the fabric bag and not attached therethrough through gluing or the like, the product enters the bag, and friction would tend to pull the liner down away from the upper corners. The incoming product together with the liner would then form a cone within the body of the bag, which would prevent the bag from filling completely. Therefore, when the bag is tied off for transport, a void space at the top is created after the cone due to the of product has been laid flat. This would create a void space and would allow product movement which may cause the bag to slump and bulge and even fall over when stacking is attempted.
Under the present state of the art, a flat top bulk bag is generally filled by hand packing the top portion of the bag. In most instances, a company would not want its employees to interrupt the filling cycle and hand pack the corners. Therefore, the bag must be sized extra tall--tall enough for accommodating the product cone during filling. This oversizing causes problems, more particularly three of concern:
(1) The higher costs of the taller bag; PA1 (2) Poor handling characteristics since any empty space within the bag, not only allows the product to move, but causes the container to change shape. This change of shape can be in the form of slumping or bulging, and creates stacking problems; and PA1 (3) A taller bag requires more hang height for discharging the product from the bottom discharge. This extra needed height can prevent some companies from being able to utilize bulk bags at all.
Therefore, there is a need in the industry for a solution to this problem in properly filling bulk bags so as to avoid stacking problems during storage and shipment.